The Red Sox have put former top prospect Henry Owens on outright waivers, taking him off the 40-man roster, a baseball source said Wednesday.

The 40-man roster was full after the Red Sox protected players ahead of the Rule 5 draft. Putting Owens on waivers exposes him to other teams and also allows the Red Sox to add a player to the 40-man roster. Any major leaguer acquired via trade or as a free-agent signing would need a 40-man space.

It wasn't immediately known if the Sox were making space preemptively, because they will eventually need likely multiple spaces, or if a player acquisition was imminent. Two baseball sources speculated a move was likely sooner rather than later, and one noted it was probably just a matter of time before Owens' spot in particular was needed.

Owens, a tall 25-year-old lefty, has always had a high ceiling but has had severe control problems. He was a 36th overall draft pick in 2011 and has 85 big league innings with a 5.19 ERA. He walked 24 in 63 innings in 2015, and walked 20 in 22 innings in 2016. In 2017, between Double-A and Triple-A, he walked 115 in 126 innings.

Owens was Baseball America's No. 2 prospect in the Sox system for two straight years, heading into 2014 and 2015.

The Baseball Show Podcast: Should we be confident in the Red Sox rotation?

The Baseball Show Podcast: Should we be confident in the Red Sox rotation?

0:21 - With less than two week before the beginning of the 2018 season, the Red Sox don’t have all of the answers for their rotation. Lou Merloni and Evan Drellich project their Opening Day rotation and discuss the lack of depth in it.

4:39 - Will Boston’s version of the ‘Killer B’s’ return in full force this season? Lou and Evan analyze the performances of Mookie Betts, Xander Bogaerts, Jackie Bradley Jr. and Andrew Benintendi.

10:07 - Buy or sell? John Farrell will find another managerial position this season; J.D. Martinez will have a better season than Aaron Judge and Giancarlo Stanton; Dave Dombrowski has put the best possible team out there for 2018.